[gdb/testsuite] Fix section matching in find_pc_sect_compunit_symtab

When running test-case gdb.base/list-ambiguous.exp with target board readnow,
we run into:
...
FAIL: gdb.base/list-ambiguous.exp: list ambiguous_fun
...

The test-case contains two static functions ambiguous_fun, one in
list-ambiguous0.c and one in list-ambiguous1.c.

The list command is supposed to show both, but only the one from
list-ambiguous0.c is shown.

This is due to the section check in find_pc_sect_compunit_symtab.  It checks
whether the candidate compunit_symtab contains a symbol that has the required
section.  This check is only done for GLOBAL_BLOCK symbols.

The check succeeds for the compunit_symtab for list-ambiguous0.c, because it
contains main, but it fails for list-ambiguous0.c because it has no global
symbols.

Fix this by extending the section check to STATIC_BLOCK symbols.

Tested on x86_64-linux.

gdb/ChangeLog:

2020-10-27  Tom de Vries  <tdevries@suse.de>

	* symtab.c (find_pc_sect_compunit_symtab): Include STATIC_BLOCK
	symbols in section check.

gdb/testsuite/ChangeLog:

2020-10-27  Tom de Vries  <tdevries@suse.de>

	* gdb.base/list-ambiguous-readnow.exp: New file.

1 files changed, 22 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.base/list-ambiguous-readnow.exp b/gdb/testsuite/gdb.base/list-ambiguous-readnow.exp
new file mode 100644
index 0000000..347a71b
--- /dev/null
+++ b/gdb/testsuite/gdb.base/list-ambiguous-readnow.exp
@@ -0,0 +1,22 @@
+# Copyright 2020 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Run list-ambiguous.exp with -readnow.
+
+save_vars { GDBFLAGS } {
+    append GDBFLAGS " -readnow"
+
+    source $srcdir/$subdir/list-ambiguous.exp
+}